Researchers developed a safe way to deliver arsenic through the bloodstream

Researchers
at Northwestern
University combined a drug therapy, which is effective
against blood cancers but not solid tumors, with nanotechnology and
the end result was a combatant of a powerful
type of breast cancer that is most common in young,
African-American women.

This
aggressive cancer, called triple negative breast cancer,
cannot be treated by any sort of life-saving therapies or traditional
chemotherapy. More often than not, women with triple negative breast
cancer have a low chance of survival.

The
drug therapy, arsenic trioxide, which is now commonly used by Western
oncologists for certain types of leukemia, is not effective against
solid tumors on its own because it is excreted too quickly after
being injected into the bloodstream for it to work. The amount if
arsenic trioxide injected into the body cannot be increased either,
due to its toxicity.

But
now, researchers have combined the arsenic trioxide with a
nanoparticle called a nanobin, which travels undetected after
entering the bloodstream until it reaches the tumor and "attacks"
it directly. The nanobin contains nanoparticulate arsenic trioxide
embedded within a liposome (a tiny, thick vessel), and is cloaked in
a chemical that both extends the nanobin's life and prohibits other
cells from seeing it as it passes through the bloodstream. In
addition, exposure of the toxic drug to normal normal tissue as it
moves through the bloodstream is limited, and when the nanobin
reaches the blood vessel of the tumor, the arsenic nanoparticles
are released and buried in the abnormal cells of the tumor.

Richard
Ahn, a student in the medical scientists training program at
Northwestern, along with Vince Cryns, associate professor of medicine
and an endocrinologist at Northwestern Medicine, and Tom O'Halloran,
director of the Chemistry of Life Processes Institute at
Northwestern, have all authored
a research paper on the nanobin, which was published
in Clinical
CancerResearch on
July 15.

The
nanobin was first tested on mice that contained triple negative
breast cancer tumors. Some mice received the nanobin while others
received regular arsenic trioxide therapy. The nanobin proved
to decrease
tumor growth while arsenic trioxide alone was not effective
at all.

"The
anti-tumor effects of the arsenic nanobins against clinically
aggressive triple negative breast tumors in mice are extremely
encouraging," said Cryns. "There's an urgent need to
develop new therapies for poor prognosis triple negative breast
cancer."

The
development of this arsenic nanoparticle has opened the door to many
other opportunities, such as making other existing cancer drugs,
which have been set to the side due to their level of toxicity or
because they're excreted too quickly, more effective in cancer tumor
treatment. Researchers are now looking to improve the nanotechnology
associated with cancer treatment by "decorating the nanobins
with antibodies that recognize markers on tumor cells to increase the
drug's uptake by the tumor." They'd also like to find a way to
deliver two drugs within the same liposome to the tumor.

"Everyone
said you can't use arsenic for solid tumors," saidO'Halloran.
"That's because they didn't deliver it the right way. This new
technology delivered
the drug directly to the tumor, maintained its stability and
shielded normal cells from the toxicity. That's huge."